Mechanical classifier



F. E. MARCY.

MECHANICAL CLASSIFIER.

APPLICATION FILED MAY25. I9I8.

Patented June 10, 1919.

3 SHEETS-SHEET I.

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F. E. MARCY.

MECHANICAL CLASSIFIER.

APPLICATION FILED MAY 25, 191B.

Patented J 11116 10, 1919.

3 SHEETS-SHEET 2.

F. E. MARCY.

MECHANICAL CLASSIFIER.

, APPLICATION FILED MAY 25. l9l8.

1,306,188. PatentedJune 10, 1919.

3 SHEETS-SHEET 3.

W/ TNESSEJ #w asag lNVENTOR.

ATTO/P/VE X 11 n SA FRANK n. IVlARCY, on SALT LAKE CITY, UTAH.

MECHANICAL CLASSIFIER.

Specification of Letters Patent.

Patented June 10, 1919.

Application filed May 25, 1918. Serial No. 236,488. i

To all whom it mac concern:

Be it known that I, FRANK- E. M-AROY, a cit-izenofthe United States,residing at Salt Lake City, in the county of Salt Lake and State ofUtah, have invented certain new and useful Improvements in MechanicalClassifiers, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings, forming apart hereof. f i

The present invention is directed to improvements in what are known inore dressing as mechanical classifiers in contradistinction to thepurely hydraulic type of machine in which the agitation is effected byan upward. current of clean water through which .the coarse or heavyparticles of the material under treatment arecaused to fall,

. and by which the fine particles or fines are separated from thecoarser particles or sands. The classifier under consideration may beused in circuit with ore grinding mills, serving the specific purpose ofreturning the coarse sands which form a compocoarse sands from floatingaway, the fine nent part of the finished product of the mill, back tothe mill for further grinding. The object sought of course is to effecta separation between the coarse sands and fines without the use ofscreens, the latter being impractical for sizes finer than 40 mesh. Sofar as concerns the immediate improvement herein,

one of the objects sought is to provide a classifierwhi-ch will remove amaximum or any desired quantity or character of fines and prevent theirreturn to the mill wlth the coarser sands requiring further treatment orregrindmg. A further ob ect is to provlde means for varying thecharacter of agitation imparted to the pulp,- producingat pleasure anupward or downward current, or mere agitation, and thereby effectlvelycontrolling; the classification of the material. A further.

object is to provide means for feeding the pulp to the classifier belowthe surface of the pool or plane of overflow to preventany materialbeing however free to rise through the pulp to the surfaceand pass offwith the overflow. A further obj ectis to prevent the fine "sandsfromtaking adirection away.

from the overflow (or toward the conveyer) the tendency of the finestotake the wrong direction in this type of machine being due to thecirculationset up by the conveyor plowing through the pulp. A furtherobject is to provide a classifier which will treat a maximum quantity ofmaterial in a minimum amount of time; one which is simple inconstruction and containing a minimum number of parts; and onepossessing further and other advantages better apparent from thefollowing detailed description in connection with the accon panyingdrawings in which- Figure 1 represents a side elevationof my improvedclassifier; Fig. 2 is a. top plan thereof with feed hopper omitted; Fig.3 is a vertical cross-section on the zig-zag line 3+3 of Fig. 2; Fig. 4is a rear end elevation; Fig. 5 is an end view of the tail pulley ordrum of the belt conveyer; Fig, 6 is an elevation of the lower end ofthe stirrer shaft showing the stirring blades set at an angle to theplane of rotation thereof; Fig. 7 is a vertical longitudinal sectionaldetail on the zigzag line 77 of Fig. 2; and Fig. 8 is an elevation ofthe lower end of the stirrer shaft showing the stirring blades setparallel to the planeiof rotation thereof;

cferring to the drawings, 1, represents an oblong tank terminating atone (the lower) end in a relatively deep portion forming a sorting basinor compartment C, and in a relatively shallow portion or extension D atthe opposite (or upper) end, the level of the pulp or water line in thedeep portion being indicatedby the dotted line a" in Fig. 1. The maximumdepth of the pulp in the sorting compartment will of course depend onthe inclination or pitch of the inclined bottom a of the tank, the planeof overflow from said compartment being along the upper edge of thevertical terminal wall 6 of the tank. The overflow from the sortingcompartment is caught in a launder 2 by which it is conducted to anysuitable point for further treatment and the recovery of the fines.Operating within the sorting compartment C on each side of the mediallongitudinal line or axis of the tank 1 is a vertically disposed stirrershaft 3, the shafts being supported by the timbers T as shown or in anyother suitable mechanical manner. The stirrer shafts are operated fromatransverse shaft 4: disposed across the tops of the timbers T, the saidshaft having rotation imparted thereto by means of a belt B leading fromthe adjacent end of a parallel driveshaft5 supported in suitable bearingblocks 6 at the upper end of the shallow portion D of the tank. withstep pulleys P and P respectively over which the belt B passes, and bymeans of v which the speeds of the shafts may be reguthe stirrer shafts,the pinions l3 engaging the pinions 1 1 of the respective shafts onopposite sides whereby the shaft 4. imparts to the stirrer shafts 8simultaneous rotation in opposite directions (see arrows Fig- 2). Thelower end of each stirrer shaft terminates in a square hub orenlargement 15, opposite each face of which is screwed a blade oragitator 16, the blade being held against rotation by a setscrew 17carried by the hub and driven firmly against the screw stem 18 of theblade (Fig. 6). The blades being rotatable about the axes of the screwstems 18 may be adjusted to any angle or pitch relative to the(horizontal) plane of rotation of the stirrer shaft, as shown in Figs. 6and 8. In Fig. 6 the blades are set at an angle to the rotation plane;and in Fig. 8 they are set parallel thereto. They may be set to anyangle between the horizontal and vertical positions as clearly obviousfrom the draw ings. The shaft 5 has rotation imparted thereto from thebelt pulley 19, a loose pulley 19 being mounted adjacent to the tightpulley 19 as well understood in the art.

The outer face of the belt conveyer 11 is provided with a series oftransversely disposed angle bars 20 which are slightly bowed or archedoutwardly (Fig. 1) to conform to the crowned peripheries of the drums 10and 12. The legs of the angle bars projecting from the beltform rakes orscrapers whose free edges travel in proximity to the outer sweep of theblades 16 and operate close to the upper surface of the inclined bottoma, of the tank, thereby carrying the sands from the sorting compartmentto the upper end of the tank where the sands discharge into the inclinedlaunder 21 whence they are conducted to the mill for regrinding- Asshown in the drawings, the bars 20 extend beyond each side of the belt11, the center of the belt being disposed along the medial longitudinalaxis of the tank. T0 impose proper tension on the belt the bearings orblocks 6 supporting the drum shaft 5 (and shaft 9) are made adjustableas well.

understood in the art.

It was pointed out above that in classifiers of the type underconsideration the fine ma- The shafts 4 and 5 are provided terial has atendency to flow over in the direction of the conveyer as indicated bythe dotted arrow in Fig. 1, whereas it should 7 flow toward theoverfiowedge e of the wall 1 Z). In the present embodiment of my invention thistendency of the fines to flow in the 7 wrong direction (toward theconveyer) is overcome or arrested by the side aprons 22, these being inthe form of sheet metal strips supported on angle brackets 23 secured tothe sides of the deep portion of thetank, said aprons being disposed'atan incline corresponding tothe pitch of the upper lap of the beltconveyer 11, the lowerportions of the aprons describing substantially asemi-v circle (Fig. 7). conformable to the curvature of the periphery ofthe tail drum 12, and

terminating below. the center line ofxsaid' drum. The upper ends of theaprons extend above the pulp line at, the iniier'longitudinal edgesthereof being spaced sufficiently from the adjacent or side edges of"the conveyor belt toprevent rubbing against the belt.

The aprons. are moreover disposed slightly chanical manner.

To prevent any coarse sands from floating away by way of the overflowfromthe sort ing compartment, I mount across thetank a feed box orhopper 2 1 the discharge The aprons are in the namouth 24; of whichextends below the pulp line 9:, the-pulp being discharged from thehopper preferably at apointbetweeir the stirrer shafts 3 and the taildrum 12. By introducing the feed below the surfaceof the pool, or pulpline w, thefine particles 7;

are permitted to rise up through the pulp and be discharged by wayofthe'overfiow, the coarsesands remaining behind; NVere the pulpdischarged on top of the pool,

some of the coarse sands would float'away' and become mixed with the'finesthereby resulting in imperfect classification. The separation ofthe fines from the coarsesands is thus enhanced by disclnrging the pulpinto the compartment C below the surface of the pool.

The operation is substantially asfoll'owsz' The pulp" (water mixed withthe crushed ore or other material) is delivered to the hopper 24: fromany suitable source, the hopper discharglng the material at a convenientpoint beneath the surface of the pool or pulp line' a: so that none ofthe .coarse sands can float:

away over the edge 2 (Fig. 1). Rotation being imparted to the shaft 5clockwise (see arrow in Fig. 1) the pinion 7 on said shaft will impart acounterclockwise. rotation to the gear wheel 8. .andto the drum 10 carried by the shaft 9, thereby imparting a corresponding movement to thebelt collveyer 11 as shown by the arrows in Fig, 1. Through theinstrumentality of the belt B, rotation will be imparted to the shaft l(Fig.2) and from said shaft to the stirrer shafts 3, 3, as clearlyobvious from. the drawings. vention of course is to separate thev finesfrom the coarse sands, the object sought being to keep the fines afloat.in the pulp inthe sorting chamber and cause them to move toward theoverflow edge e of the wall I), and at the same time cause the coarsesandsto be dropped and advanced toward the tail drum 12 andthescraperblades 20 of the conveyer, said scrapers pushing the sands upward alongtheinclined bottom a and causmg the1r dlscharge over the upper edge ofsaid inclined bottom into. the launder 21. To effect this separation dueregard must be had for the intensity and character of the agitationbrought about by the revolving blades 16. The degree of their pitch tothe rotation plane will determine the character of current and degree ofagitation, and likewise the path of advance of the coarse sands.Depending on the degree and direction of that pitch we may produce anupward current or downward current; or, by turning the blades into the.plane of. rotation as shown in Fig. 8 (in contradistinction to theangular disposition shown in Fig. 6), we may produce mere agitationwithout any defined upward or downward current. The adjustability of thepitch of the blades to the plane of rotation is an important feature inthe present invention as it enables me to adjust the agitation to thecharacter of the pulp operated on and thereby secure efi'ectiveseparation of the fines from the coarse sands. In the present embodimentof the invention the fines are prevented from taking the wrong directionby the deflecting aprons or diaphragms 22, which, together with the belt11 (barring clearances of course) form an efiective barrier against anytendency on-the part of the fines to flow toward the conveyer. In factthe aprons and belt quite well segregate the sorting compartment C fromthe rest of the tank 1.

' The coarse sands of course are caused to ad- The main purpose of, thein-,

any desired speed may be imparted to the stirrer shafts 3, 3. The blades16 may of course be set to such a pitch and thespeed of rotation of thestirrer shafts be so increased as to cause a portion of the coarse sandsto be carried away with the fines over the overflow edge e. If theagitation is moderate a larger volume of sands will settle than would bethe case where the agitation was violent. .Again, the pulleys P, P, maybe changed so that any desired relation of speeds between the beltconveyer and stirrer shafts maybe obtained, thereby permitting the speedof the belt to be increased in the event of a settling of largequantities of coarse sands. Obviously the classifier is not restrictedin its application to the treatment of ores, but may be used 011 anymaterial capable of classification. The apparatus. may be changed inmany details without a departure from the nature or spirit of myinvention. Features shown but not alluded to are well known in the artand a description thereof is here unnecessary. The term belt as usedherein is not to be restricted to an imperforate endless member as shownbut is to be understood as including any endless member imperforate oropen and made of any material whatsoever to which suitable rakes orscrapers such as 20 or their equivalents may be attached.

Having described my invention what I claim is: p

1. A classifier of the character described comprising a tank having abottom sorting compartment or. basin provided with an overflow, and aninclined portion leading above the pulp line in said basin, meansextending below the pulp line to a point between said inclined portionand overflow for feeding a charge of pulp to the basin, a belt conveyerin said tank having one end dipping below the pulp line and the oppositeend terminating at a point above the pulp line, agitating devices in thebasin positioned basin provided with an overflow, and an inclinedportion leading above the pulp line in the basin, means extending belowthe pulp line to a point between said inclined portion and overflow forfeeding a charge of pulp to the basin, a belt conveyer having one enddipping below the pulp line and the opposite end terminating at a pointabove the pulp line, agitating devices positioned below the pulp feedbetween the point of overflow and the adjacent end of the conveyer,means for imparting a rotary sweep to said agitating devices about anaXis through the pulp line,

' and means for adjusting the angularity of comprising a tank providedwith a sorting" chamber having an overflow, the tank hav} ing anupwardly inclined extension or per 7 tion leading from said sortingchamber, a

belt conveyer in said extension having a lower terminal in the sortingchamber and operating to conduct the coarse sands therefrom to a'pointabove and beyond thesorting chamber, a rotary stirrer shaft in' thesorting chamber between the point of overflow thereof and the adjacentend of the conveyer, pulp-feeding means discharging below the pulp lineat a point between the stirrer shaft and inclined portion ofthe tank,agitating blades on the shaft, sweeping in proximity to the adjacentterminal of the conveyor, and means for maintaining the blades at anydesired pitch or angle to the plane of rotation thereof about the axisof the stirrer shafti 4. In a classifier of the character described, atank provided with a sorting compartment having an overflow, and with aninclined extension leadingv therefrom to a point above the pulp line insaid compartment, an endless conveyer disposed in the tank and dippingat one end below the pulp line in the sorting compartment, the sides ofthe conveyer being spaced a suitable distance from the side walls of thetank, anagitating device in the sorting compartment inthe adjacent endof the conveyer, and suitable aprons or d-iaphragms spanning the spacesbetween the tank walls and the sides j of the conveyer tooffsetanytendency of the fines to flow in a direction away from theoverflowand toward the conveyer.

--5. In a classifier of the character described, a'suitableftankprovided with a sorting compcrtment having an overflow, an endlessconveyer dipping I with one end below the pulpline in the compartment adrum in the compartment for the support of the conveyer, the sidesofthe-conveyer being 7 spaced from the adjacent walls of the tank,

scrapers disposed across the conveyer andprojecting beyond the sidesthereof, suitable aprons spanning the'spac'es between the tank' wallsand "the side edges of the conveyer but clearing said edges andpositioned slightly;

below the path of travel of the scrapers and clearing said scrapers,the'said apronsbeing disposed in the general plane of travel of theupper lap of the conveyer andextending to the pulp line at the top, thelower portions dipping below the" pulp line and being curved to conformto the curvature of the drum peripher and an agitating device inthe'sorting compartment,

In testimony whereof I affix my signature,

in presence of'two witnesses. V

' FRANK E. MARGY. lVitnesses VIOLA P. DRUSHAL, ROBERT E; MARK.

Copies of this patent may be obtained for five cents each, by addressingthe C0mn1issioner..of Patents, Washington, D. G.

